According to Zimmer, Yoga philosophy is reckoned to be part of the non-Vedic system, which also includes the Samkhya school of Hindu philosophy, Jainism and Buddhism:[45] "[Jainism] does not derive from Brahman-Aryan sources, but reflects the cosmology and anthropology of a much older pre-Aryan upper class of northeastern India [Bihar] – being rooted in the same subsoil of archaic metaphysical speculation as Yoga, Sankhya, and Buddhism, the other non-Vedic Indian systems."[61][note 6]